Electric gaseous discharge apparatus



May 19, 1936. A. CLAUDE ELEG I'RIC GASEOUS DISCHARGE APPARATUS Filed001;. 22, 195].

Fig.3.

Fig." 2

3 Mm m m W e H Patented May 19,1936

PATENT OFFICE ELECTRIC GASEOUS APPARA mscnaaos 'rns Andi- Claude,Nanterre, France Application October 22;, 1931, Serial No. 570,45il InFrance November 5, 1930 4 Claims.

rare gas, and operating on the arc principle, and

which are fed by direct or alternating current, it can be appliedtoapparatus of that kind which are to be used for lighting purposes.

An'object of this invention is the maintenance of integrity of thecathode in all apparatus of this type over long periods and also formaintaining the constancy of the lighting power and of the quality ofthe light emitted by the gaseous mass contained in the apparatus.Another object of the present invention is the. application of the meansgiving the above results to any electric gaseous discharge apparatuswhich is not used for lighting purposes, and for which it would bedesirableto obtain one or several of the said results.

it is well-known that in a discharge apparatus of the herein abovementioned type working on the arc principle that although thedrop inpotcn ial at the cathode is very low, a considerable amount of energy isabsorbed by the cathode by reason oi the great intensity of the currentpassing through the device. I

The energy thus expended causes a local increase in temperature whichcan be sumcient to volatilize the material of which the cathode is,

In order to eliminate the disadvantages due to the vclatilization of thecathode material, the cathodic part ofthe discharge apparatus, that isto say that part of the apparatus which enshrouds the cathode, isconstructed so as to form stones which, during the normal operation oithe apparatus will be at a temperature sufllciently lower than that oithe gas of the apparatus, than that of the sides of the luminous columnand than that of the sides of the anodic region so that the cathodicmaterial volatilized in the cathodic space can be condensed in the saidzones. These zones however are at a temperature sumcicntly high to causethe material which has been condensed to fall in a molten state upon thebody of the cathode.

The condensation zones of the cathodic part of the apparatus can beobtained by shaping elements of the cathodic part in such a manner that(A) Certain zones of these elements are less subject to the sheets ofheat due to the electric energy absorbed at the cathode than others.

(B) Certain zones of these elements are colder than others, these lastzones being formed wholly or partly by all or part of the zonesmentioned 5 under A.

Further, a region, the normal temperature of which is considerablyhigher than that of the a luminous part and much higher than that of thecondensation zones of the cathodic region is interposed between thislatter and the luminous column. The efiects of such an arrangement is tosettle the limits of the condensation zones.' It is particularlyeffective when the difference between the temperature of the cathodiccondensation zones and the temperature of the luminous region isrelatively slight.

The arrangement can be realized in different ways for example by (A)Narrowing the luminous column at a suitable point in the same.

(B) By providing a lagging sleeve reducing cooling at the walls.

(C) By providing an auxiliary heating arrangement formed for example bymeans of all or part of the stabilization resistance of the feed circuitof the discharge apparatus.

(D) By providing a combination of several of the above-mentioned means.

In order to eliminate the disadvantages due to the spattering of thematerial of the cathode, a material obstacle is interposed between thecathode and the extreme cathodic section of the illuminating part of thegaseous column, so that no particle of material emitted in a straightline from any point of thecathode can reach the illuminating part ofthis column.

Consequently, as the particles emitted by the cathode are mainlyprojected in a straight line for substantially long stretches into raregases or mixtures of such, even in the case of the low pressures of gasused in the electric discharge apparatus, they are stopped by thisobstacle which is preferably mounted in such a way that the particlesreturn to the cathode.

By using the above-mentioned means numerous advantages are obtained someof which are cited below.

non-cathodic region of the apparatus is prevented and. con quentlyanyocclusion of the gas charge of the discharge apparatus through thesedeposits is eliminated so that on the one hand the transparency of thewalls or sides of the luminous column of the apparatus is not alteredand on the other hand the gaseous mass of the said apparatus ispreserved unchanged.

The invention is more particularly described with reference to theaccompanying drawing showing certain constructions by way of example.

,Figure 1 is an electric light discharge device constructed according tothe present invention.

Figure 2 is a detailed view on an enlarged scale of the cathodic part ofthe apparatus according to Fig. 1.

Figure 3 is a view of a first modification of the cathodic part of Fig.2.

Figure 4 is a view of a second modification of the same cathodic part.

Figure 5 is a third modification of the same cathodic part.

Figure 6 is a fourth modification of the same cathodic part.

In the various figures, the same reference numerals indicate the sameelements.

The discharge apparatus shown in Fig. 1 comprises an anodlc part iprovided with its anode l", a luminouscolumn 2 and a cathodic part 3with its cathode an In Figure 2 the cathodic part 3 is formed by acontainer 4 which is concave and fairly wide, the walls 5, 6, l, and 8,9, ill of which, not subject (or only slightly subject) to the effectsof heat due to the discharge, form the condensation zones for the vapourof the cathodic material contained in the bowl or cup H. The abovecondensation zones can also be placed outside the cathodic regionitself. They will consequently becolder than this, but sufilciently warmas stated above for causing the condensed matter to fall in a moltenstate on the cathode.

In Fig. 3, 42 shows a choke interposed between" the luminous column 2and the cathodic part 3 and which forms a section is which is at ahigher temperature than the temperature of the luminous column 2 and ofthe cathodic region.

In Fig. 4, l4 represents a member which can be either a lagging sleeveor a heating arrangement which forms a section 92 at a temperatureposits tending to be projected into the apparatus a in a straight line.

In Fig. 6 the screen 51 prevents the tendency of particles projected ina straight line from the cathode, from'ialling into the tube and acts asa material obstacle to them.

It is to be understood that the various means described above andillustrated in the figures can be utilized solely or in variouscombinations in the same discharge apparatus.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. An electric discharge apparatus for operation under arcing conditionscomprising an envelope containing at least one rare gas and divided intocommunicating cathode and discharge chambers, a cathode in the cathodechamber formed of metal volatile at the temperatures to which thecathode is heated by electrical energy passing therethrou'gh in theoperation of the apparatus, the portion of the cathode chamber betweenthe discharge chamber and the cathode constituting a condensing chamberand being constructed of a size sufficiently large relative to thecathode so that the walls thereof will be at a temperature lower thanthe boiling point and higher than the melting point'of the cathodemetal, means for maintaining a zone intermediate .the discharge andcathode chambers at a temperture higher than that of the dischargechamber, and an obstacle between the cathode and the discharge chambercapable of preventing any particles of metal projected in a straightline from any point of the cathode from penetrating into the dischargechamber.

2. Apparatus according to claim 1, in which the means for maintainingthe intermediate zone at a temperature higher than that of the dischargechamber consists of an electric resistance connected in series with theelectric supply circuit of the apparatus.

3. Apparatus according to claim 1, in which the means for maintainingthe intermediate zone at a temperature higher than that of the dischargechamber consists of heatinsulating material surrounding the apparatus atsaid zone.

4. An electric discharge apparatus for operation under arcing conditionscomprising an envelope containing at least one rare gas and divided intocommunicating cathode and discharge chambers, a cathode in .the cathodechamber formed of material volatile at the temperatures to which thecathode is heated by electrical energy passing therethrough in theoperation of the apparatus, the cathode chamber being constructedsufiiciently large relative to the cathode so that the wall thereof willbe at a temperature higher than the fusion point and lower than thecondensation point of the cathode material means for maintaining a zoneintermediate the cathode and discharge chambers at a temperature higherthan the temperature of the discharge chamber and a screen positionedbetween said zone and the cathode to prevent particles of the cathodeprojected in a straight line from entering the discharge chamber wherebylight is emitted in the discharge chamber solely by the rare gaseousfilling to the exclusion of light emitted by the material 01 thecathode.

Arman CLAUDE.

